Since the 16th century, pre-pubertal boys were castrated to prevent their voices from breaking and to ensure that they retained a high-pitched soprano, mezzo-soprano or contralto singing register. Known as castrati, these singers, with their flexible and sensuous voices, were a highly prized element of choral and opera singing. They survived in the Vatican and Roman churches until the 20th century.

Listen to a performance of Eugenio Terziani's Hostias et Preces by Alessandro Moreschi, the only castrato trained in the old traditions ever to be recorded.